Hey guys! I'm Bobby and I finally made myself an account after i've hit a dead end.

So i'm pretty mechanically inclined (i've worked on cars as a hobby of mine for YEARS) Anyways. So i just bought a 2000 3.9 4x4 Dakota. I know the valve seals going on these is a pretty common issue. I know there are 2 methods to changing the seals without pulling the head off. 1 is with rope (which comes with the risk of the rope becoming tangled or knotted inside the cyl) and 2 is an air compressor (filling the cyl with air keeping the valve pressed in the up right position and not falling into the cyl) Being that i have a compressor i opted for this method.

So I prefilled the compressor to build 60-70psi (recommended everywhere) i hook up the airline to the sparkplug via fitting adapter and hear the air rush in then escape at half the speed through the throttle body. I can feel it breeze past the butterflies it slows right around the 20psi mark but still leaks. When watching countless vids on youtube of this method on different vehicles they never encountered this issue. Engine is in TDC

I was really trying to do this without pulling the head.

Any idea's as to why the air is rushing through the throttle body? or am i missing something?

 

*UPDATE*

So after some thought I believe the intake valve is obviously not seated properly or it's it's bent. either way.. the heads are gonna have to come off.. Great..

 

your probably right.
just to make sure your at tdc on the compression stroke; look at the rockers for the cylinder in question....both springs should not be compressed and the rockers should be up at the same angle when released.

 

yup, thats how we change our valve springs on the dragster. Sounds like you've lost compression on the intake side. Run a rolling compression test....bet you'll have that hole around 80-90 psi at best. We get 150 on the dragster on a 2 year old assembly